Rotary pump

ABSTRACT

A rotary pump of the twin-screw type having a lateral inlet port at one end and an axial outlet port at the other end, the outlet port being provided with a transition member containing feed screws.

nited States Patent 1 11 3,733,152 Blackwell [451 May 15, 1973 s41ROTARY PUMP 3,198,582 8/1965 [75] Inventor: Elliott H. BlackwelL Warren,Mass. 1 p 3,467,300 9/1969 [73] Asslgnee Warren umps, Inc Warren, Mass3,535,057 10/1970 [22] Filed: Oct. 29, 1971 Primary Examiner-C. J. Husar[211 App]' 193734 Attorney-Norman S. Blodgett 52 US. cl. ..418/201 [57]ABSTRACT [51] Int. Cl. .....F0lc 1/16 A rotary pump of the twln-screwtype havlng a lateral [58] Fleld of Search ..4l8/20l inlet p at one endand an axial outlet p at the other end, the outlet port being providedwith a transi- [56] References C'ted tion member containing feed screws.UNITED STATES PATENTS l V l 2,745,643 5/1956 Kleinlein ..418/201 5Claims, 2 Drawing Figures SHEET 1 0r 2 PATENIED HAY 1 5191s INVENTOR.11101! H. Blackwell ROTARY PUMP Many technical processes involve themovement of materials which are difficult to pump; among the mostdifficult of these are the slurries and pulps that are encountered inpaper manufacturing processes and the like. Such materials may containstringy elements or elements that are very abrasive or chemicallyactive. One type of pump that has proved to be very practical in pumpingsuch materials is the rotary twin-screw type. However, even this type ofpump has proved to have a relatively short life in some applications,not only because of corrosive materials getting into the bearing, butbecause of the difficulty in causing the flow of certain materials intothe entrance port and out of the outlet port. It is possible toameliorate but not entirely to remove these problems by use of expensiveauxiliary apparatus, but the cost of doing so in the past has beenprohibitive. These and other difficulties experienced with the prior artdevices have been obviated in a novel manner by the present invention.It is, therefore, an outstanding object of the invention to provide arotary pump of a relatively simple and inexpensive nature capable ofhandling difficult materials with a minimum of maintenance problems.

Another object of this invention is the provision of a rotary pump forhandling abrasive slurries in which the possibility of damage tobearings is minimized.

A further object of the present invention is the provision of a rotarypump of the twin-screw type in which entrance of materials into one endof the screw and out of the other end of the screw is-facilitated.

It is another object of the instant invention to provide a rotary pumpof the twin-screw type in which the jamming of stringy materials at thedischarge end is prevented.

With these and other objects in view, as will be apparent to thoseskilled in the art, the invention resides in the combination of partsset forth in the specification and covered by the claims appendedhereto.

SUMMARY OF THE INVENTION In general, the invention consists of a rotarypump having a double-bored housing with a lateral inlet port at one endand an axial outlet port at the other end. Driving and driven rotors aremounted in the housing, the rotors having intermeshing helical ribs andhaving intermeshing gears to keep the rotors in synchronization witheach other. A set of bearings is located in the housing adjacent thesaid one end. A transition member is attached to the housing over theoutlet port and feed screws extend from the rotors at the said other endinto the transition member.

More specifically, the transition member has an inlet substantially thesize of the said outlet port and an outlet substantially smaller andaligned with one of the rotors. The said one of the rotors extendssubstantially entirely through the transition member to the outletthereof, while the other rotor extends only part way.

BRIEF DESCRIPTION OF THE DRAWINGS The character of the invention,however, may be best understood by reference to one of its structuralforms, as illustrated by the accompanying drawings, in which:

FIG. 1 is a plan view with portions broken away of a pump embodying theprinciples of the present invention, and

FIG. 2 is a sectional view of the invention taken on the line II-Il ofFIG. 1.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring to FIGS. 1 and 2, itcan be seen that the rotary pump, indicated generally by the referencenumeral 10, is provided with a housing 11 having twin bores 12 and 13.Extending from the bores at one end is a lateral inlet port 14 and atthe other end an axial outlet port 15. A driving rotor 16 is mounted inthe bore 12, while a driven rotor 17 is mounted in the bore 13. Therotors l6 and 17 are provided with intermesh ing helical ribs 18 and 19which operate to pump fluidlike materials in the well-known manner. Therotor 16 and the rotor 17 are also provided with intermeshing gears 21and 22, respectively, to maintain the rotors in rotationalsynchronization with each other. A first set of bearings 23 and 24 ofthe anti-friction, roller type are located at the ends of the rotors l6and 17, respectively, in the housing 11 to support the rotors. At thesame ends of the rotors but on the opposite side of the gears 21 and 22are provided another set of bearings 25 and 26 which are also of theanti-friction, roller type to assist in the support of the rotors. Thehousing 11 is provided with a wall 27 which serves as one wall of anenclosure for the inlet port 14. In this wall is mounted a pair of seals28 and 29 which serve to seal the entrance of the rotors 16 and 17,respectively, into the enclosed part of the housing.

The portion of the rotors l6 and 17 underlie the inlet port 14 and areprovided with thin-walled, open-mesh feed screws 31 and 32. Extendingoutwardly of the housing 1 1 over the outlet port 15 is a transitionmember 33 which, as is obvious in FIG. 2, constitutes in general anextension of the bores 12 and 13, but, as is indicated in FIG. 1, istapered across the bore 13 into alignment with the bore 12. The rotor 16is provided with a thin-walled open-mesh feed screw 34, while the rotor17 is similarly provided with a feed screw 35. The transition member 33has an inlet 36 which is substantially the size of the outlet port 15 ofthe housing 11 and it has an outlet 37. which is substantially smallerand which is aligned with the rotor 16.

The rotor 16 extends entirely through the transition member 33 to theoutlet 37, while the rotor 17, because of the taper of the adjacent wallof the transition member, extends only part way. The feed screws 34 and35 associated with the rotors are carried mostly on the parts of therotors that lie in the transition member, although they extend partlyinto the respective bores. The bearings 23 and 25 are shown asconstituting substantially the entire support for the rotors l6 and 17,so that they are, in effect, cantilevered and lie within their bores 12and 13, respectively.

The operation of the rotary pump 10 will now be readily understood inview of the above description. The material to be pumped enters the pumpthrough the inlet port 14 and falls into the container surrounding thefeed screws 31 and 32. These screws forward the material toward the openend of the bores 12 and 13 where it is picked up by the helical ribs 18and 19 manner to carry the material along the bores and to increase itspressure as it passes. The material is extruded from the ends of thebores into the transition member 33 where it is picked up by the feedscrews 34 and 35, which carry it into the outlet 37 of the transitionmember. The transition member is, of course, suitably provided withflanges in the usual way to permit its incorporation into the fluidsystem.

It can be seen that the bearings 23, 24, 2S, and 26 carry the rotors ina somewhat cantilevered manner, aside from their slight support by theseals 28 and 29 and by the slight engagement of the ribs 18 and 19 withthe surfaces of the bores 12 and 13, respectively. In any case, theseals 28 and 29 prevent the fluid (which may be of an abrasive orcorrosive nature) from gaining access to the bearings 23, 24, 25, and26, so that they are guaranteed an extraordinarily long life. In thefailure of the material to enter the pump portion, this is overcome bythe action of the feed screws 31 and 32, while any tendency toaccumulate at the output of the pump portion is overcome by the feedscrews 34 and 35.

It is obvious that minor changes may be made in the form andconstruction of the invention without departing from the material spiritthereof. It is not, however, desired to confine the invention to theexact form herein shown and described, but it is desired to include allsuch as properly come within the scope claimed.

The invention having been thus described, what is claimed as new anddesired tosecure by Letters Patent l. A rotary pump, comprising a. adouble-bored housing with a lateral inlet port at one end and an axialoutlet port at the other end,

b. a driving and a driven rotor mounted in the housing, the rotorshaving intermeshing helical ribs, the rotors also having intermeshinggears to keep the rotors in synchronization with each other,

c. a set of bearings located in the housing at the said one end tosupport the rotors,

d. a transition member attached to the housing over the outlet port, thetransition member having an inlet substantially smaller and aligned withone of the rotors, the said one of the rotors extending entirely throughthe transition member to the outlet thereof, while the other rotorextends along part way, and

e. feed screws extending from the rotors at the said other end into thetransition member.

2. A rotary pump as recited in claim 1, wherein the said bearings areanti-friction bearings and constitute substantially the entire supportfor the rotors.

3. A rotary pump as recited in claim 1, wherein the feed screws arecarried on the parts of the rotors that lie in the transition member.

4. A rotary pump as recited in claim 3, wherein the rotors are providedwith feed screws co-extensive with the inlet port.

5. A rotary pump as recited in claim 2, wherein the bearings consist oftwo axially-separated bearing for each rotor, the gears being locatedbetween the bearings.

1. A rotary pump, comprising a. a double-bored housing with a lateralinlet port at one end and an axial outlet port at the other end, b. adriving and a driven rotor mounted in the housing, the rotors havingintermeshing helical ribs, the rotors also having intermeshing gears tokeep the rotors in synchronization with each other, c. a set of bearingslocated in the housing at the said one end to support the rotors, d. atransition member attached to the housing over the outlet port, thetransition member having an inlet substantially smaller and aligned withone of the rotors, the said one of the rotors extending entirely throughthe transition member to the outlet thereof, while the other rotorextends along part way, and e. feed screws extending from the rotors atthe said other end into the transition member.
 2. A rotary pump asrecited in claim 1, wherein the said bearings are anti-friction bearingsand constitute substantially the entire support for the rotors.
 3. Arotary pump as recited in claim 1, wherein the feed screws are carriedon the parts of the rotors that lie in the transition member.
 4. Arotary pump as recited in claim 3, wherein the rotors are provided withfeed screws co-extensive with the inlet port.
 5. A rotary pump asrecited in claim 2, wherein the bearings consist of twoaxially-separated bearing for each rotor, the gears being locatedbetween the bearings.